The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Drains are ubiquitous features in homes and businesses, providing removal of waste and excess water, typically to centralized sewage or gray water treatment systems. Unfortunately connection to such systems can provide a route for entry of unwanted contents of such systems to such homes and businesses. Such unwanted contents include waste water, untreated sewage, gases, and insect and/or rodent pests.
In order to prevent or reduce such occurrences various valve systems have been devised. Examples of such valve systems include U.S. Pat. Nos. 7,900,288, 9,027,172, and International Patent Application Publication No. WO 2017/091692. All publications identified herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
While such devices are effective in preventing unwanted intrusion and/or contamination via a drain the placement of such devices within the fluid flow path can potentially reduce the rate of fluid flow through the drain. This is particularly true when the drain is relatively narrow (e.g. less than about 2 inches/5.1 cm).
U.S. Pat. No. 8,627,519 describes a pool drain with an inlet and a sump, with blades positioned within the fluid path that direct the incoming water and provide laminar flow within the drain pipe. The stated purpose for these is to prevent or reduce entanglement of debris that enters the pool drain, thereby reducing the formation of blockages. It is not clear that these provide any improvement in flow rate through the drain. Similarly, United States Patent Application Publication No. 2018/0112407 describes the use of a drain cover for a roof drain inlet that includes an arrangement of fins that prevent the formation of a vortex by draining rainwater and the provide high volume laminar flow within the drain pipe. It is not apparent, however, if such a device can be adapted to conventional domestic or industrial use where projections from a drain cover may be susceptible to impact damage. In addition, it is not evident that such approaches are effective in relatively narrow diameter drains.
Thus, there is still a need for devices and methods that increase fluid flow rates through narrow drains, particularly in the presence of drain valve systems.